Over-end winding of yarn



ovEafENQ-WINDING oF YARN Filed Aug. 21, 196'? PACKAGE DIAMETER (INU/E5)A lllnleys United States Patent O 3,451,209 OVER-END WINDING F YARNDouglas Chisholm Bisset, Alan Keith Dunnell, Clive Williams Hooper, andKenneth Andrew Key, Pontypool, England, assignors to Imperial ChemicalIndustries Limited, London, England, a corporation of Great BritainFiled Aug. 21, 1967, Ser. No. 661,859 Claims priority, application GreatBritain, Sept. 1, 1966, 39,113/ 66 Int. Cl. D02g; D01h 13/00; B65h 53/12U.S. Cl. 57-156 4 Claims ABSTRACT 0F THE DISCLOSURE Regions ofpatterning in a yarn package, due to e.g. ring-tilt, are avoided byshifting between at least 3 spindle speed values during the windingcycle.

The invention concerns improvements in or relating to the over-endwinding of yarn.

Over-end winding of yarn, as on the well-known ring spinning machine, ispractised when it is desired to impart a twist to the yarn by the act ofwinding.

A common instance of such over-end Winding is to be found in thedrawtwisting of synthetic polymer iilaments; and the present inventionwill be described in relation to such drawtwisting, although it is to beunderstood that the invention is not limited thereto.

A `drawtwister is essentially a downtwister in which are incorporatedroll mechanisms for drawing undrawn yarn. Usually, such mechanismsconsists of nip rolls rotated at a given speed acting as feed rolls; anda draw roll and separator roll combination, the former roll of which isrotated at the required higher speed to effect the drawing action on thetilaments in question. From the draw roll, the drawn filaments proceedin a generally downward direction to a thread guide positioned axially,or near-axially, of the spindle of a ring and traveller ring spinningmechanism. This thread guide is sometimes known as the balloon guide, asthe yarn is ballooned beneath it by virtue of the rotation of thetraveller around the ring. The filaments are then wound up on a bobbinmounted on the rotating spindle, by passage around the traveller whichis itself rotated around the ring and by reciprocation of the ring, inits rail, tray or other carrier, in the axial direction of the spindleaccording to the builder motion required for the particular yarn packageto be wound on the bobbin.

It is a quite usual artilice to tilt the ring of the ring spinningmechanism in order that the filaments shall be laid on to the bobbin andyarn package in helical coils having a wavy path rather than a flathelical one. An angle of tilt of between 3 and 6 is usual; although anangle even as low as 1 may be selected and will donate an appreciablewave component to the laying-on path of the yarn. Rings are notgenerally set to a greater degree of accuracy than within i-l/f.

Such ring tilt is at least a major factor predisposing the formation ofregions of patterning at certain radii of the package build, owing tothe coincidence of adjacent coil loci. The incidence of these variousregions of patterning, which patterning is to be avoided both from thetechnical point of view of package stability and yarn take-offcharacteristics and from the point of View of appearance, can becalculated, e.g. by analogue computer, for any given process involving adrawtwisting wind-up; and hence it is possible to so programme theWinding conditions that the regions of patterning which normally wouldoccur shall be avoided.

One method of programming the winding conditions which has been proposedis to alternate the spindle speed between two values, switching from oneto the other and back again, and so on, when the stages of winding arecalculated to be reached at which patterning will occur at therespective spindle speed to be departed from.

The conditions leading to patterning are related to the wind ratio: thatis, the ratio of the number of revolutions per minute of the point ofwinding-on the package to the number of revolutions per minute of thetraveller. Patterning will be severe at and around integral values ofiwind ratio; and consequently the spindle speed programme is devised,according to the above known method, so that the speed is shifted to thealternate one when the winding conditions approach a value of windratio, for the primary speed, at which patterning will occur, and isthen shifted back to the primary one when similarly patterning is due tobe encountered at the alternate speed.

Although the above method appears theoretically t0 provide an answer tothe patterning problem in over-end winding, we have found that inpractice it is close to impossible to select the respective alternatespindle speeds to produce a winding programme that effectively avoidsthe patterning conditions throughout the winding of a full-Weight, e.g.4 lb., yarn package. This is because the occurrence of patterning is notrestricted to the moments during winding when the pattern-inducing windratios are established, but is prolonged for a period either side ofthose times; and therefore, unless the regions of patterning are lessthan the spacing between pattern-inducing wind ratios, which willcertainly not be the case at the worst ratios, if t-hese are to beencountered in the package, it will not be possible merely byalternation of speeds to avoid such regions altogether.

Again, especially when the adjacent pattern-inducing wind ratios are notmultiples of one another, it is most likely that the attempt to avoidone such wind ratio by shifting to the alternate speed will merelyresult in a collision with another such wind ratio.

The invention, therefore, is based on the proposition that the spindlespeed in an over-end winding process is programmed to be shifted betweenat least three selected speeds in a manner so as to avoid the calculatedregions of patterning in the yarn package being wound.

This invention comprises a method of winding yarn by over-end winding onto a package formed with the aid 0f a rotating spindle, wherein thespeed of rotation of the spindle is programmed so as to be shiftedbetween at least three selected values of speed in a manner such as toavoid calculated regions of patterning that would otherwise occur in thepackage being wound.

Shifting between the speeds may be in a cyclical, or in a repeatedsequential, progression; or, alternatively, it may be in apre-determined but unordered manner calculated, e.g. graphically, toprovide the best pattern-avoidance programme. v

For instance, if three spindle speeds A, B and C are to be used, theshift may be cyclically from A to B to C to B to A and so on, orrepeated sequentially from A to B to C to A to B to C and so on.Alternatively, any programme of unordered shifts can be predetermined,as, for example, A to C to B to C to A to B.

The selected speed are obviously chosen so as to be as close to theoptimum speed for the process as possible, compatible with providing therequired disparity in speed to enable the calculated patterning regionsto be avoided.

Shifting from one speed to another is achieved in an abrupt manner tocross straight through, or move quickly away from the patterning region,i.e. the invention is not concerned with any gradual variations inspindle speed taking place over the entire winding period or asubstantial part thereof.

On the other hand, a high frequency low amplitude variation in speedabout any or all of the selected speeds may be imposed, in order toscramble the wind ratio and thus to disperse any patterning which maynot have been completely avoided by the abrupt shifts in spindle speed.The scrambling conditions should not, of course, be such as to cause thewind ratio to re-enter the main patterning regions.

Although the use of three spindle speeds has been instanced above, it isto be understood that any number greater than two may be employedaccording to the invention, although it is contemplated that any givenprogramme will always be worked out for the minimum number of speedscompatible with effective pattern avoidance.

The spindle speed shift programme is first calculated for the particularprocess, and then that programme is applied to a controller for avariable speed device driving the spindle shaft of the machine. Theprogramme can be applied in sundry ways, the motivation for whichderives either from the mechanical operation of parts of the machine,for instance the builder mechanism, or from external programming means,as for instance timing mechanism, punched cards, tapes, etc.; notoperatively connected with the machine.

Whilst the invention is applicable to the winding of yarn packages onall kinds of bobbin or tube, it will be understaood that the particularprogramme to be selected will be affected by the shape of the tube, e.g.as to whether it is frusto-conical or cylindrical.

As an example of the invention, the following conditions were applied toa process in which 70 denier 30 lament yarn of polyhexamethyleneadiparnide nylon 66 was produced by drawing at a draw ratio of 3.36 at aspeed of 2,500 feet/minute, and was wound-up by a ring and travellersystem of a Rieter drawtwister in a 3 lb. double taper yarn package on a1.85" diameter tube with a long-to-short traverse build:

Draw roll peripheral speed Constant at 2,500 feet/minute, (or

such speed at to produce a winding on speed of that value). Ring tilt 3Spindle speeds:

A 8,500 r.p.m. B 9,120 r.p.m. C 9,850 r.p.m.

Spindle speed shift programme (A-C-B-A-C-B-A-C-B-A-B-A-B-C) By the aboveprogramme, it was possible to wind the package so that substantially n0patterning Was present at any radius thereof, particularly avoiding thepatterning regions corresponding to the wind ratios 1:2, 2:5, 1:3, 2:7and 1:4, as shown in the accompanying drawing which is a graph of thespindle speed/yarn speed ratio against package diameter. The patterningregions are shown as shaded bars across the graph; and the spindlespeed/yarn speed ratio line is plotted across these regions, avoidingthem all, as the package diameter rises from 1.85 inches to 5 inchesthrough the full period of winding.

We claim:

1. In a method of winding yarn on a machine in which method the yarn iswound over-end of a package mounted for rotation on a spindle and thespeed of rotation of the spindle is changed during the Winding of thepackage in a manner so as to avoid regions of patterning in the packagethat would otherwise occur owing to the existence of certain windratios, the improvement comprising changing the spindle speed abruptlybetween at least three selected values according to a programme,successive changes being made as the wind ratio approaches values givingrise to any substantial degree of patterning whereby regions ofpatterning in the package are avoided.

2. A method as in claim 1 including monitoring a variable in the windingoperation to obtain a signal and wherein the spindle speed is changed inaccordance with a signal derived from said signal.

3. A method as in claim 2 wherein the signal is derived from monitoringthe building motion of the winding operation.

4. A method as in claim 1 wherein a high frequency low amplitudevariation in speed is imposed on the spindle about at least one of theselected speeds in order to scramble the wind ratio and thus to disperseany patterning which may not have been completely avoided by the abruptshifts in spindle speed.

References Cited UNITED STATES PATENTS 2,658,689 ll/1953 Waldrop 242-1813,137,987 6/1964 Potts 57-55.5 3,235,191 2/1966 Engel-man et al.242-18.1 3,241,779 3/1966 Bray et al. 242-181 3,325,985 6/1967 Bucher242-263 XR JORDAN FRANKLIN, Primary Examiner.

W. H. SCHROEDER, Assistant Examiner.

U.S. Cl. X.R. 57-93; 242-18.1

